This invention relates to an improvement on a vented-type leak resistant motor cycle battery.
The prior art vented type motor cycle batteries with free electrolyte are usually provided with a single vent tube that is fitted with a flexible, polymeric exhaust pipe for the safe exit of acidic mist and exhaust gases. Under the actual service condition, however, this arrangement is not entirely reliable because many a time the flexible exhaust pipe gets detached from the batteries. Thus, there exists some possibility of hazard due to leakage of the acidic mist together with the exhaust gases within the battery housing under the actual service conditions.
In view of the above, there is a trend in the industry to switch over to sealed type valve regulated lead-acid (VRLA) batteries for motor cycle applications, which are essentially leak-proof as they do not contain any free electrolyte. However, the sealed type batteries are significantly more expensive and also involve relatively complex manufacturing processes. Besides, the sealed type VRLA batteries can only be fitted on modern 2-wheelers equipped with an improved charging system suitable for the sealed type batteries.
However, for a vast range of vented-type batteries, there is a need to make them leak-resistant in all directions for safety as also to dispense with the need for the flexible exhaust pipe. It should be noted that the motor cycle batteries in service may be subjected to high degree of tilt in all directions. Therefore, from the safety point of view, it is highly desirable for the batteries to have leak-resistance characteristics.
Thus far, there has been no major attempt in the industry to impart leak-resistant characteristics to the flooded motor cycle batteries. Hence, the present innovation aims at bridging this technology gap in the vented-type motor cycle battery range.
The motor cycle battery cover conventionally comprises two parts, namely a main cover and a vent chamber cover heat-sealed to the main cover. However, there is a possibility of spillage of electrolyte when the battery is not in the upright position.
Accordingly, it is a principal object of the invention to provide a vented type motor cycle battery having safe-guards against leakage in all directions for a substantial length of time even when the battery is not in an upright position.
In accordance with one aspect of the invention, there is provided a vented-type leak-resistant motor cycle battery comprising: a housing in which a plurality of cells are mounted; a battery cover sealed to an upper end of the housing in a liquid tight manner so that the battery cover overlies the cells each having a vent chamber, a filling hole and a filling plug; and a vent chamber cover sealed to the main cover in a liquid tight manner, characterized in that the battery cover is provided with a vent line extending in a longitudinal direction of the battery cover in flow communication with the spaces above the cells and having an exit end tilted upwardly and that a vent cap assembly is fitted to the vent line at the tilted exit end.
In the aforementioned aspect of the present invention, the end of the vent line opposite to the exit end thereof may be closed and the exit end of the vent line may be preferably tilted or sloped downwardly toward the opposite end of the vent line.
Furthermore, there may be preferably vent chambers for the respective cells provided inside of the vent line and communicating with each other. The vent chamber furthest from the exit end of the vent line may have an exit hole in communication with the vent line.
The vent chambers may be formed of baffle sheet and the vent cap assembly may be more preferably formed so that gases from the exit end of the vent line contact a gas filter through a labyrinth.
The labyrinth may be provided in a vent cap and may comprise a vent hole in communication with the tilted exit end of the vent line, a first vertical hole extending from the vent hole to the outer periphery of the vent cap, a helical path on the outer periphery of the vent cap and connected at its one end to the first vertical hole and at its other end to a second vertical hole extending to the center of the vent cap so as to be in communication with the gas filter.
In accordance with another aspect of the invention, there is provided a vented-type leak-resistant motor cycle battery comprising: a housing in which a plurality of cells are mounted; a battery cover thermally sealed to an upper end of the housing so that the battery cover overlies the cells each having a filling hole, a filling plug and a vent chamber; terminals mounted on the battery cover and connected to the cells; and a vent chamber cover thermally sealed to the battery cover, characterized in that the battery cover is provided with a vent line adjacent to the cells, being in flow communication with the spaces above the cells and having an exit end tilted upwardly and that a vent cap assembly is fitted to the vent line at the tilted exit end.
The vent line may preferably have a gentle downward slope from the exit end towards the other end of the vent line.
In a preferred embodiment of the present invention, the vent cap assembly comprises a vent cap fitted to the tilted exit end of the vent line, and a gas filter fitted into the vent cap for allowing the vented gas to escape.
The vent cap preferably has a vent hole in communication with the tilted exit end of the vent line, a first vertical hole extending from the vent hole to the outer periphery of the vent cap and a helical path on the outer periphery connected at its one end to the first vertical hole and at its other end to a second vertical hole extending to the center of the vent cap so as to be in communication with the gas filter.
The gas filter may be a water-repellant microporous gas filter. The microporous filter has preferably a grain size of about 270 microns.
The gas filter can be press-fitted into the vent cap and closed by means of a filter cover having a hole for escape of the vented gas.
In the aforementioned aspect of the present invention, the vent chambers may be provided inside of the vent line, corresponding to each cell in the main cover with the downward slope, opening into a funnel-like drain hole to facilitate drainage of electrolyte into the respective cells when the battery is in the upright position, each vent chamber may be in flow communication with the space above each cell and the vent chambers may be in flow communication with each other, each vent chamber may be provided with a gas escape hole at an elevated position with respect to the drain hole so as to allow the escape of the gases even when the drain hole is full of electrolyte, and the vent chamber which is remote from the tilted exit end of the vent line is provided with an exit hole so that any electrolyte leaking from the cell has to pass through the vent chambers before exiting out of the vent chamber through the exit hole towards the tilted exit end of the vent line. The chambers may be preferably formed of baffle sheet.
In the battery according to the present invention, the battery cover is such that even if the battery is tilted by 90 degree on either side, the electrolyte height is below the tilted exit end of the vent line so as to make the battery leak-resistant in any of these positions. Also, this arrangement provides an air lock, which prevents electrolyte leakage even when the battery is kept in the inverted position for a considerable length of time such as more than two hours, for example.